Chain-like zircona (ZrO 2 ) nanofibers were prepared by microwave sinter-ing without any surfactants or solid templates. Microwave sintering was conducted in a multimode microwave cavity with TE666 resonant mode at 2.45 GHz. Carbon particles were used to activate unique thermal processes when mixed with ZrO 2 precursor. The sintering condition was at 1300°C for 10 min. Samples were characterized by XRD, SEM, TEM techniques. It was found that both monolithic and tetragonal ZrO 2 co-existed in samples prepared from the mixture of ZrO 2 precursors and carbon by either microwave or conventional sintering. Only m-ZrO 2 exists in samples prepared by ZrO 2 precursors without carbon. ZrO 2 appeared as chain-like nanofibers, which might be attributed to a so-called carbon-induced self-assembly growth mechanism.